| Summary: | 碩士 === 國立中央大學 === 應用地質研究所 === 85 === Non-destructive of Civil Engineering Structures by Using GPR
Techniques Jaw-Nian Chen
Abstract
A new application of ground penetrating radar (GPR) to inspect
a civil engineering structure is being studied. This technique
is to transmit an electromagnetic wave (radar wave) to a
structure which is being examined, a then,reflected and/or
diffracted waves will come from some buried anomalies. These
returned signals are detected by a receiving antenna on the
ground surface. The characteristics of these waves depend on
the geometry and/or dielectric properties of the target. The
way of detecting the buried targets or defects is a non-
destructive, it is quite different to the conventional
inspection methods applied to civil engineering,such as drilling
or cutting. In addition, the final result of GPR is a continuous
section rather than a point response as drilling does.
The application of GPR in this paper are grouped into 5
category; namely,(1) pavement investigation , (2) bridge studies
, (3) general architectural application, (4) geotechnical
engineering studies and (5) tunnel inspection, respectively .
Based on the results of pavement studies , the thickness of
asphalt and roadbed are measurable. In addition, the type of
roadbed also can be recognized. In bridge investigation, GPR
can map the inside structure of a bridge , and the exposed
depth of buried bridge piles caused by water flow.Location of
rebar , protective thickness of rebar, thickness of cement
concrete, and permeated position in structure can be obtained in
the general architectural studies. For geotechnical
engineering investigation, the positions of buried objects
(e.g., pipes) can be located before digging. Finally, the
thickness of lining ,and position of rebar behind the lining
can be detected in a tunnel inspection.
The case studies indicate that GPR techniques are succeeded in
all of aforementioned non-destructive application in civil
engineering problems. GPR does have the potential for further
applied in more civil engineering problems.
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